Today, I'm writing about how to create animated PNG (APNG) files, such as this one: I first wrote about APNG files last February. An APNG file is a valid PNG image file that uses file metadata in a... read more >>

Here's an interesting snippet I learned while working on today's blog post: Mathematician Jacob Bernoulli asked for a logarithmic spiral to be engraved on his tombstone. Here's an example of a such a... read more >>

One of the discrete-time Fourier transform properties that many people learn is that if a sequence is conjugate symmetric, , then the Fourier transform is real. Therefore it... read more >>

Thanks to Kimo Johnson and Perttu Ranta-aho for responding to my custom spatial transformation challenge. Contents Kimo's submission ... read more >>

Blog reader David A. asked me a while back about how to transform an image based on some mathematical function. For example, the online paper "Visualizing complex analytic functions... read more >>